| 摘要 |
<p>The folding ladder is of non-combustible material, having a number of U-section rungs mounted on ropes, strips etc. The rungs are stacked on top of each other so as to leave between them a space accommodating the intervening lengths of rope. The two arms (5,6) of the U-section diverge from the tread surface (7), so as to straddle those of the rung below, and the lengths of rope etc are accommodated in a single space. The rungs may be curved upwards at the ends. The rungs can be of aluminium plate or sheet of less than 1 mm thickness.</p> |
